This invention relates to a novel liquid crystalline compound and a liquid crystal composition containing the compound.
Liquid crystal substances and compositions containing the same have been used for various display devices, utilizing the dielectric anisotropy (abbreviated to .DELTA..epsilon.) and optical anisotropy (abbreviated to .DELTA.n) in the liquid crystal phases thereof.
Liquid crystal display modes include various modes such as electrically controlled birefringence mode (ECB mode), twisted nematic mode (TN mode), super-twisted birefringence mode (SBE mode), dynamic scattering mode (DS mode), guest-host mode, etc., correspondingly to the electrooptical effect applied.
Liquid crystal materials used for display devices should be together provided with various characteristics such as broad mesomorphic range, low viscosity, large positive .DELTA..epsilon. value or negative .DELTA..epsilon. value, less temperature dependence of electrooptic characteristics (especially threshold voltage) of display devices within a wide temperature range, etc., depending on the display mode of the devices and further depending on various characteristics required for display elements.
At present, however, there is no single compound which is practically usable in the aspects of mesomorphic range, driving voltage and response properties. Thus, a mixture of several kinds of liquid crystal compounds or a mixture of several kinds of liquid crystal compounds with a compound having latent liquid crystal properties or a non-liquid crystal compound has been practically used.